Nevadella

{{Short description|Extinct genus of trilobites}} {{Automatic taxobox | fossil_range = Late Atdabanian, {{Geological range|524|522}} | image = Nevadella eucharis USNM PAL 60079.jpg | image_caption = ''Nevadella eucharis'', type specimen | taxon = Nevadella | authority = Raw, 1936 | subdivision_ranks = Species | subdivision = * ''N. eucharis'' (Walcott, 1913) (type) synonym ''Callavia eucharis'' * ''N. baculenta'' (Fritz, 1972) * ''N. cartlandi'' (Raw in Walcott, 1910) synonyms ''Callavia cartlandi'', ''C. cobboldi'', ''C. brevioculata''<ref>{{cite journal|last= Lieberman|first= B. S.|year= 2001|title= Phylogenetic Analysis of the Olenellina Walcott, 1890 (Trilobita, Cambrian)|journal= Journal of Paleontology|volume= 75|number= 1|pages= 96–115|url= http://www.bioone.org/doi/full/10.1666/0022-3360%282001%29075%3C0096%APAOTOW%3E2.0.CO%3B2|doi=10.1666/0022-3360(2001)075<0096:PAOTOW>2.0.CO;2|s2cid= 85656419|url-access= subscription}}</ref> * ''N. keelensis'' Abe, 2010 * ''N. mountjoyi'' (Fritz, 1972) * ''N. perfecta'' (Walcott, 1913) synonym ''Callavia perfecta'' }}

left|thumb|Several cephalons of ''Nevadella perfecta'', with undamaged glabellas, also showing the strikingly wide cephalic margin'''''Nevadella''''' is an extinct genus of trilobites, fossil marine arthropods, with species of average size (about {{convert|5|cm|in|disp=or}} long). It lived during the late Atdabanian stage, which lasted from 530 to 524 million years ago during the early part of the Cambrian Period.<ref name="Sepkoski">{{cite journal | last = Sepkoski| first = Jack| title = A compendium of fossil marine animal genera (Trilobita entry)| journal = Bulletins of American Paleontology| volume = 364| page = 560| year = 2002| url = http://strata.ummp.lsa.umich.edu/jack/showgenera.php?taxon=307&rank=class| access-date = 2008-01-12 }}</ref>

== Etymology == The name is derived from ''Nevadia'', a related genus.

== Taxonomy == ''Nevadia'' predates ''Nevadella'' and may include its direct ancestor.

=== Species previously assigned to ''Nevadella'' === * ''N. burri'' = ''Pleisionevadella burri''

== Description == The body of ''Nevadella'' is very flat dorso-ventrally. The general outline of its thin, lightly calcified exoskeleton is inverted drop-shaped. The front is rounded, widest at the back of the headshield (or cephalon), and tapering from there to an eventually rounded termination. The central area of the cephalon (or glabella) is distinctly tapered forward, sides slightly concave, but wedging out slightly in the frontal half and with a rounded front (like the silhouette of a slim pawn). The glabella and the frontal margin almost or entirely touch (in jargon: the preglabellar field is short or absent). Cephalic margin at least as wide as the most frontal thoracal segment. The thorax has 17 to 23 segments, gradually diminishing in size. The pleural spines are long and sickle-shaped. The tailshield (or pygidium) is very small and subquadrate in shape.<ref name='Whittington'>{{cite book |author=H. B. Whittington|title=Treatise on Invertebrate Paleontology. Part O, Revised. Trilobita |chapter=Introduction, Order Agnostida, Order Redlichiida |year=1997|display-authors=etal}}</ref>

== Distribution == Fossils of ''Nevadella'' have been found in the late Atdabanian of the USA (California, Nevada) and Canada (Cordilleran region). * ''N. eucharis'' is known from the Middle Member of the Poleta Formation, Esmeralda County, Nevada, USA.<ref>[http://paleodb.geology.wisc.edu/cgi-bin/bridge.pl?action=basicCollectionSearch&collection_no=10496 Paleobiology Database]{{Dead link|date=January 2026 |bot=InternetArchiveBot }}</ref> * ''N. keelensis'' is known from the Sekwi Formation, Northwest Territories, Canada.<ref>F. R. Abe, B. S. Lieberman, M. C. Pope, K. Dilliard (2010). "New information on olenelline trilobites from the Cambrian Sekwi Formation in northwestern Canada". ''Canadian Journal of Earth Sciences'', 2010, '''47''' (12): 1445–1449.[http://www.nrcresearchpress.com/doi/abs/10.1139/E10-073]</ref><ref>{{Cite web |url=http://trilobites.lifedesks.org/node/690 |title=Life Desks, Trilobites on line |access-date=2012-03-04 |archive-date=2013-05-14 |archive-url=https://web.archive.org/web/20130514051603/http://trilobites.lifedesks.org/node/690 |url-status=dead }}</ref> * ''N. mountjoyi'' is known from the Mural Formation, north slope of Mount Mumm, Alberta, Canada.<ref>{{Cite web |url=http://trilobites.lifedesks.org/node/696 |title=Life Desks, Trilobites on line |access-date=2012-03-04 |archive-date=2013-04-30 |archive-url=https://web.archive.org/web/20130430074918/http://trilobites.lifedesks.org/node/696 |url-status=dead }}</ref> * ''N. perfecta'' is known from the Mahto Formation, Mumm Peak on the west side of Hitka Pass, western Alberta, Canada.<ref>U. S. National Museum, Catalogue No. 60082.</ref>

== Ecology == Contemporary taxa that also occur in the so-called "Nevadella" Zone include ''Esmeraldina'', ''Holmiella'', ''Palmettaspis'', ''Bradyfallotaspis'', ''Geraldinella'', ''Paranevadella'', ''Nevadia'', ''Buenellus'', and ''Cirquella''.<ref name='Whittington'/>

== Habitat == ''Nevadella'' species were probably marine bottom dwellers, like all Olenellina.

== References == {{Reflist}}

Category:Olenellina Category:Redlichiida genera Category:Cambrian trilobites of North America Category:Paleozoic life of Alberta Category:Paleozoic life of British Columbia Category:Cambrian genus extinctions